Analysis of Physical Oceanographic Data from Bonne Bay, September 2002 September 2004

Transcription

1 Physics and Physical Oceanography Data Report -1 Analysis of Physical Oceanographic Data from Bonne Bay, September September Clark Richards and Brad deyoung Nov. 9 Department of Physics and Physical Oceanography Memorial University of Newfoundland St. John s, Newfoundland A1B 3X7

2 Abstract Acoustic Doppler Current Profilers were deployed between September and September on the sill of the East Arm in Bonne Bay, a glacial fjord in Gros Morne National Park on the west coast of Newfoundland. The moorings were deployed over the time period to measure the velocity of water flowing over the sill, in order to better understand the exchange dynamics of the system. In addition to the current meter data, several cruises were conducted in June to collect hydrographic data in the Bay, specifically temperature, salinity and density profiles. The data reveal the structure of the tidal flow over the sill and the interannual variability of the flow structure and transport. Meteorological data from the area are also presented. ii

3 Acknowledgements We thank the crew and captain of the Louis M. Lauzier for their help in this oceanographic study. The hydrographic data were primarily collected by Drs. P. Snelgrove and D. Deibel. Funding for this project was provided from an NSERC Grant to B. de Young. iii

4 Table of Contents Abstract. ii Acknowledgements.. iii Table of Contents. iv List of figures v List of tables.. x Introduction... 1 Data processing. References.. iv

5 List of figures Figure 1: Bathymetry of Bonne Bay... Figure : mooring positions...9 Figure 3: 3 mooring positions... Figure : mooring positions...11 Figure : Low pass filtered ADCP data from mooring M1-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity....1 Figure : Low pass filtered ADCP data from mooring M-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity....1 Figure 7: Low pass filtered ADCP data from mooring M3-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity Figure : Low pass filtered ADCP data from mooring M-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity Figure 9: Low pass filtered ADCP data from mooring M1-3. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity....1 v

6 Figure : Low pass filtered ADCP data from mooring M-3. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity...1 Figure 11: Low pass filtered ADCP data from mooring M3-3. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity....1 Figure 1: Low pass filtered ADCP data from mooring M-3. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity....1 Figure 13: Low pass filtered ADCP data from mooring M1-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity....1 Figure 1: Low pass filtered ADCP data from mooring M-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity....1 Figure 1: Major axis angles for data at each depth bin calculated using Emery, 1997 pp 3. Angles are given in degrees, where o is East. The horizontal line indicates the bottom Figure 1: Major axis angles for 3 data at each depth bin calculated using Emery, 1997 pp 3. Angles are given in degrees, where o is East. The horizontal line indicates the bottom vi

7 Figure 17: Major axis angles for data at each depth bin calculated using Emery, 1997 pp 3. Angles are given in degrees, where o is East. The horizontal line indicates the bottom....1 Figure 1: ADCP data for M1- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Figure 19: ADCP data for M- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Figure : ADCP data for M3- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Figure 1: ADCP data for M- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Figure : ADCP data for M1-3 rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Figure 3: ADCP data for M-3 rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Figure : ADCP data for M3-3 rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Figure : ADCP data for M-3 rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Figure : ADCP data for M1- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Figure 7: ADCP data for M- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig vii

8 Figure : Wind stress at Rocky Harbour over the period for which there is ADCP data. Calculated according to Gill Figure 9: Wind stress at Rocky Harbour from January 1993 to September. Calculated according to Gill Figure 3: Air temperature at Rocky Harbour over the period for which there is ADCP data. White line is filtered with a cutoff of ~ days.... Figure 31: Air temperature at Rocky Harbour from January 1993 to June. White line is a monthly average.... Figure 3: ADCP instrument temperatures for.... Figure 33: ADCP instrument temperatures for Figure 3: ADCP instrument temperatures for....7 Figure 3: Transect stations from June /7. Vertical profiles were done at S1 and S with a towed horizontal profile in between.... Figure 3: Vertical and horizontal temperature, salinity and sigma-t profiles from S1 to S, 1: to 1:3 GMT June....9 Figure 37: Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, 17: to 1:9 GMT June....3 Figure 3: Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, 19:37 to :1 GMT June Figure 39: Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, 3:3 to 3: GMT June Figure : Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, :3 to : GMT June viii

9 Figure 1: Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, :1 to : GMT June Figure : Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, 11:1 to 11:7 GMT June Figure 3: South arm CTD stations and vertical transect line....3 Figure : Temperature, salinity and sigma-t along the South arm of Bonne Bay, June. Numbers indicate CTD stations in Fig. 3. Stations and were collected June 9, while stations 1, 3 and were collected June 13. This is the cause of the bumpiness of the contours near the stations Figure : Sill-1 and Sill- positions from June 9 to June Figure : Temperature time series at Sill-1 and Sill-. The middle plot indicates the tidal state Figure 7: Salinity time series at Sill-1 and Sill-. The middle plot indicates the tidal state Figure : Sigma-t time series at Sill-1 and Sill-. The middle plot indicates the tidal state Figure 9: East arm to Gulf of St. Lawrence CTD stations and vertical transect line... Figure : Temperature, salinity and sigma-t over the sill of Bonne Bay, June. Numbers indicate CTD stations. Stations 1- were collected on June, while stations 7- were collected on June ix

10 List of tables Table 1: Location and Summary of Bonne Bay - ADCP moorings... Table : Serial numbers and frequencies of Bonne Bay - moorings... Table 3: Amplitude (cm/s) of the major axis of selected tidal constituents of the current at a depth of 1m...7 Table : Amplitude (cm/s) of the minor axis of selected tidal constituents of the current at a depth of 1m...7 Table : Phase (degrees relative to Greenwich) of selected tidal constituents of the current at a depth of 1m...7 x

11 Introduction We are interested in the exchange over the sill of water between the east arm of Bonne Bay and the Gulf of St. Lawrence (see Figure 1). This exchange can be regulated by many different factors, including tides, wind stress, and freshwater runoff and largely determines the properties of deep water on the landward side of the sill. The moorings were deployed on the sill to try and get a sense of the 3 dimensional nature of the flow. The and 3 moorings were deployed directly on the bottom, while the moorings were about 1 metre above the bottom. The mooring positions for, 3 and are shown in Figures, 3 and. The moorings were arranged to provide the best coverage of the deepest part of the sill, approximately in the middle of it. Each ADCP was also equipped with a temperature sensor that measured the temperature of the water at the location of the instrument. The instruments were all RDI beam sentinel ADCP s at a frequency of 3 khz, except for M1-3 and M-3 which were khz and khz respectively. In addition to the current data, meteorological data were obtained from Environment Canada for the period from January 1993 to June for the nearby weather monitoring station at Rocky Harbour. Meteorological data for the summer of were obtained from a weather monitoring station installed on the roof of the Bonne Bay Marine Station. Also, during June of several cruises were conducted to gather temperature, salinity, and density data in the area surrounding the sill, in the arms of the bay, and out into the Gulf of St. Lawrence. A cruise on June th and 7 th collected vertical and 1

12 horizontal profiles on the sill over several tidal cycles. These data are presented as plots of temperature, salinity and σ T at and between the two stations on either side of the sill. A similar cruise was performed between June 9 th and 11 th, but without the horizontal surface profile. These data are plotted as time series contours. Data Processing The ADCP data were processed in a manner similar to the approach of Tittensor et al.. First the data were extracted from the instrument output files and missing data was interpolated linearly from the data surrounding it. The data were collected in 1 metre depth bins for most instruments, though M1-3 and M-3 were sampling with. metre bins. The backscatter was corrected following standard techniques (Deines, 1999) utilizing factory-set instrument characteristics as well as environmental factors such as the sound absorption coefficient and the speed of sound at each depth cell. These parameters, together with the slant range to each depth cell, were then used in the sonar equation to estimate the backscatter coefficient. The velocity was then decomposed into u and v components, and filtered using a th order forward and reverse Butterworth low pass digital filter with a cut-off of 3 hours (along with the backscatter) and plotted. The data were also corrected for the changing surface elevation due to tides by adjusting the data from each time step according to the level of maximum backscatter intensity. The filtered and surface-corrected data were then plotted.

13 The hourly wind and air temperature data for Rocky Harbour were obtained from Environment Canada as a series of text files. The data were examined for large peaks which were manually removed, and any short gaps were linearly interpolated. The data were extracted from these files, decomposed into u and v components, then converted to wind stress (Gill, 19) and re-saved in a MATLAB format. The data set for 1997 from Rocky Harbour was incomplete and so was substituted with data from CornerBrook. Also, for a short period in 1999 the anemometer malfunctioned, but because this period did not correspond with ADCP data period it was ignored. Wind data for the period from June 19 th to September 19 th was obtained from a weather station installed at the Bonne Bay Marine Station. The data were extracted from text files and missing points were interpolated. Vertical CTD profiles were collected using an SBE- probe, while the horizontal surface profiles were collected with an SBE-19 probe. Only the temperature, salinity and density data are presented here. The CTD data were extracted from the instrument output text files and re-saved in a MATLAB format. The up-cast portion was removed, as was the part of the data from when the instrument was sitting at the surface. The raw data were then plotted in several different ways. The data from the June th sill survey were plotted as vertical and horizontal profiles of temperature, salinity, and σ T. The data from the June 9 th sill survey were plotted as a time series contour at the two stations on either side of the sill. The data from the South Arm, East Arm, and out into the Gulf of St. Lawrence were plotted as two-dimensional vertical contour maps. An analysis of the major axis direction for each mooring was performed (Emery, 199) and the results are shown in Figures 1, 1 and 17. By solving for the eigenvalues 3

14 of the covariance matrix for the u and v velocities, the angle of the principle axis θ p can be found using: u' v' tan(θ p ) = u' v' where u' = u u and v' = v v. The angles calculated through this process were then used to rotate the u and v axes for each depth at each mooring to visualize the through and cross channel velocities. Tidal analysis for the moorings was performed using Foreman tidal analysis scripts for MATLAB (Pawlowicz, ) and the results for selected moorings are shown in Tables and 3.

15 References Deines, K. L., 1999: Backscatter estimation using broadband acoustic Doppler current profilers. Proceeding of the IEEE th working conference on current measurement, San Diego, CA. Emery, W. J. and R. E. Thomson, 1997: Data analysis methods in physical oceanography. 1 ed. Elsevier Science Ltd. Gill, A. E., 19: Atmosphere-ocean dynamics. Vol. 3, International Geophysics Series, Academic Press. Pawlowicz, R., B. Beardsley, and S. Lentz, : Classical tidal harmonic analysis including error estimates in MATLAB using T_TIDE. Computers & Geosciences,, Tittensor, D. P., B. de Young, and J. Foley, : Analysis of physical oceanographic data from Trinity Bay, May - August. Physics and Physical Oceanography Data Report -. Department of Physics & Physical Oceanography, Memorial University of Newfoundland.

16 Table 1: Location and summary of Bonne Bay - ADCP moorings Mooring Latitude ( o N) Longitude ( o W) Depth (m) Averaging period Bin size M min 1m M min 1m M min 1m M min 1m M min.m M min.m M min 1m M min 1m M min 1m M min 1m Start day Sept. 7 Nov. Sept. 7 Sept. 7 Nov. 3 Oct. 3 Nov. 3 July 19 3 June 1 June 1 End day Nov. 1 July 17 3 June 3 Nov. 1 May 3 June 1 June 19 Apr. 3 Sept. 1 Sept. 17 Table : Serial numbers and frequencies of Bonne Bay - moorings. Mooring Instrument Serial Number Frequency M1-3 khz M khz M3-9 3 khz M khz M khz M-3 9 khz M khz M khz M1-3 khz M khz

17 Table 3: Amplitude (cm/s) of the major axis of selected tidal constituents of the current at a depth of 1m. M1- M- M3- M- M1-3 M-3 M3-3 M-3 M1-3 M-3 O K N M S K M Table : Amplitude (cm/s) of the minor axis of selected tidal constituents of the current at a depth of 1m. M1- M- M3- M- M1-3 M-3 M3-3 M-3 M1-3 M-3 O K N M S K M Table : Phase (degrees relative to Greenwich) of selected tidal constituents of the current at a depth of 1m. M1- M- M3- M- M1-3 M-3 M3-3 M-3 O K N M S K M

18 Figure 1: Bathymetry and topography of the Bonne Bay region. Bathymetry data obtained from the Geological Survey of Canada and the digitization of Chart, topography data from the Shuttle Radar Topography Mission by the U.S. Geological Survey. Distance between grid points in the data set is approximately.3 metres.

19 Figure : mooring positions 9

20 Figure 3: 3 mooring locations

21 Figure : mooring positions 11

22 etres ADCP data, M time, days from Jan v (cm s -1 ) u (cm s -1 ) EA (db re (πm) -1 ) Figure : Low pass filtered ADCP data from mooring M1-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity. etres 1 ADCP data, M time, days from Jan v (cm s -1 ) u (cm s -1 ) EA (db re (πm) -1 ) Figure : Low pass filtered ADCP data from mooring M-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity. 1

23 etres 1 ADCP data, M time, days from Jan v (cm s -1 ) u (cm s -1 ) EA (db re (πm) -1 ) Figure 7: Low pass filtered ADCP data from mooring M3-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity. etres ADCP data, M time, days from Jan v (cm s -1 ) u (cm s -1 ) EA (db re (πm) -1 ) Figure : Low pass filtered ADCP data from mooring M-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity. 13

24 ADCP data, M1-3 - u (cm s -1 ) etres time, days from Jan v (cm s -1 ) EA (db re (πm) -1 ) Figure 9: Low pass filtered ADCP data from mooring M1-3. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity. ADCP data, M-3 etres time, days from Jan v (cm s -1 ) u (cm s -1 ) EA (db re (πm) -1 ) Figure : Low pass filtered ADCP data from mooring M-3. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity 1

25 etres ADCP data, M time, days from Jan v (cm s -1 ) u (cm s -1 ) EA (db re (πm) -1 ) Figure 11: Low pass filtered ADCP data from mooring M3-3. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity. ADCP data, M-3 etres time, days from Jan v (cm s -1 ) u (cm s -1 ) EA (db re (πm) -1 ) Figure 1: Low pass filtered ADCP data from mooring M-3. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity. 1

26 ADCP data, M1- etres time, days from Jan v (cm s -1 ) u (cm s -1 ) EA (db re (πm) -1 ) Figure 13: Low pass filtered ADCP data from mooring M1-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity. ADCP data, M- etres time, days from Jan u (cm s -1 ) v (cm s -1 ) EA (db re (πm) -1 ) Figure 1: Low pass filtered ADCP data from mooring M-. Cutoff is 3 hours. Top: East-west speed (cm/s). Middle: North-south speed (cm/s). Bottom: Spherically corrected backscatter intensity. 1

27 M1- M- M3- M depth (m) Figure 1: Major axis angles for data at each depth bin calculated using Emery, 1997 pp 3. Angles are given in degrees, where o is East. The horizontal line indicates the bottom. M1-3 M-3 M3-3 M depth (m) Figure 1: Major axis angles for 3 data at each depth bin calculated using Emery, 1997 pp 3. Angles are given in degrees, where o is East. The horizontal line indicates the bottom. 17

28 M1-3 M depth (m) Figure 17: Major axis angles for data at each depth bin calculated using Emery, 1997 pp 3. Angles are given in degrees, where o is East. The horizontal line indicates the bottom. 1

29 Through and cross channel low pass filtered ADCP data, M cm s etres cm s time, days from Jan. 1 - Figure 1: ADCP data for M1- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig. 1 Through and cross channel low pass filtered ADCP data, M cm s -1 - etres time, days from Jan. 1 - cm s -1 Figure 19: ADCP data for M- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig. 1 19

30 Through and cross channel low pass filtered ADCP data, M cm s -1 - etres time, days from Jan. 1 - cm s -1 Figure : ADCP data for M3- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig Through and cross channel low pass filtered ADCP data, M cm s -1 etres cm s time, days from Jan. 1 - Figure 1: ADCP data for M- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig. 1

31 Through and cross channel low pass filtered ADCP data, M cm s -1 etres time, days from Jan cm s -1 Figure : ADCP data for M1-3 rotated for through and cross channel flow at each depth bin according to the angles specified in Fig. 1 Through and cross channel low pass filtered ADCP data, M cm s etres cm s time, days from Jan Figure 3: ADCP data for M-3 rotated for through and cross channel flow at each depth bin according to the angles specified in Fig. 1 1

32 - Through and cross channel low pass filtered ADCP data, M cm s etres time, days from Jan cm s -1 Figure : ADCP data for M3-3 rotated for through and cross channel flow at each depth bin according to the angles specified in Fig. 1 Through and cross channel low pass filtered ADCP data, M cm s -1 etres time, days from Jan cm s -1 Figure : ADCP data for M-3 rotated for through and cross channel flow at each depth bin according to the angles specified in Fig. 1

33 Through and cross channel low pass filtered ADCP data, M cm s -1 etres time, days from Jan. 1 - cm s -1 Figure : ADCP data for M1- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig. 17 Through and cross channel low pass filtered ADCP data, M cm s -1 etres time, days from Jan. 1 - cm s -1 Figure 7: ADCP data for M- rotated for through and cross channel flow at each depth bin according to the angles specified in Fig. 17 3

34 . Wind Stress at Rocky Harbour Tau-x, N/m Tau-y, N/m Time, days from Jan. 1 Figure : Wind stress at Rocky Harbour over the period for which there is ADCP data. Calculated according to Gill 19.. Wind Stress, Bonne Bay Tau-x, N/m Tau-y, N/m Year Figure 9: Wind stress at Rocky Harbour from January 1993 to September. Calculated according to Gill 19.

35 Air Temperature at Rocky Harbour 3 o C Time, days from Jan. 1 Figure 3: Air temperature at Rocky Harbour over the period for which there is ADCP data. White line is filtered with a cutoff of ~ days. Air temperature at Rocky Harbour, Hourly and Monthly average 3 o C Year Figure 31: Air temperature at Rocky Harbour from January 1993 to June. White line is a monthly average.

36 M 1 ADCP instrument temperatures in o C for M3 M M time, days from Jan. 1 Figure 3: ADCP instrument temperatures for. M M3 ADCP instrument temperatures in o C for M M time, days from Jan. 1 3 Figure 33: ADCP instrument temperatures for 3.

37 ADCP instrument temperatures in o C for Summer 1 M M time, days from Jan. 1 Figure 3: ADCP instrument temperatures for. 7

38 Figure 3: Transect stations from June /7. Vertical profiles were done at S1 and S with a towed horizontal profile in between.

39 T, S, and σ T for Section 1-1: to 1:3 (GMT) June S1-1: tow Elapsed time (min) S-1: o C 3 3 Salinity 1 3 σ T Figure 3: Vertical and horizontal temperature, salinity and sigma-t profiles from S1 to S, 1: to 1:3 GMT June. 9

40 T, S, and σ T for Section - 17: to 1:9 (GMT) June S1-17: tow Elapsed time (min) S-1: o C 3 3 Salinity 1 3 σ T Figure 37: Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, 17: to 1:9 GMT June. 3

41 T, S, and σ T for Section 3-19:37 to :1(GMT) June S1-19: tow Elapsed time (min) S-: o C 3 3 Salinity σ T Figure 3: Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, 19:37 to :1 GMT June. 31

42 T, S, and σ T for Section - 3:3 to 3: (GMT) June 7 S1-3: tow Elapsed time (min) S-3: o C Salinity 3 σ T Figure 39: Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, 3:3 to 3: GMT June 7. 3

43 T, S, and σ T for Section - :3 to : (GMT) June 7 S1-: tow Elapsed time (min) S-: o C 3 Salinity σ T Figure : Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, :3 to : GMT June 7. 33

44 T, S, and σ T for Section - :1 to : (GMT) June 7 S1-: tow Elapsed time (min) S-: o C Salinity 3 σ T Figure 1: Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, :1 to : GMT June 7. 3

45 T, S, and σ T for Section 7-11:1 to 11:7 (GMT) June 7 S1-11: tow Elapsed time (min) S-11: o C Salinity 1 3 σ T Figure : Vertical and horizontal temperature, Salinity and sigma-t profiles from S1 to S, 11:1 to 11:7 GMT June 7. 3

46 Figure 3: South arm CTD stations and vertical transect line. 3

47 3 1 Temperature, Salinity and σ T of the south arm of Bonne Bay, June Distance, (km) Figure : Temperature, salinity and sigma-t along the South arm of Bonne Bay, June. Numbers indicate CTD stations in Fig. 3. Stations and were collected June 9, while stations 1, 3 and were collected June 13. This is the cause of the bumpiness of the contours near the stations. 37

48 Figure : Sill-1 and Sill- positions from June 9 to June 11 Tidal height, m Temperature timeseries at Sill-1 and Sill Hours (GMT) from midnight June 9 Figure : Temperature time series at Sill-1 and Sill-. The middle plot indicates the tidal state

49 Tidal height, m Salinity timeseries at Sill-1 and Sill Hours (GMT) from midnight June Figure 7: Salinity time series at Sill-1 and Sill-. The middle plot indicates the tidal state. Tidal height, m σ T timeseries at Sill-1 and Sill Hours (GMT) from midnight June Figure : Sigma-t time series at Sill-1 and Sill-. The middle plot indicates the tidal state

50 Figure 9: East arm to Gulf of St. Lawrence CTD stations and vertical transect line

51 Temperature, Salinity and σ T over the sill of Bonne Bay, June Distance, (km) Figure : Temperature, salinity and sigma-t over the sill of Bonne Bay, June. Numbers indicate CTD stations. Stations 1- were collected on June, while stations 7- were collected on June 13. 1